Exhaust emission regulation to engine devices serving as internal combustion engines has become more and more strict in recent years, and various measures have been proposed for engine devices in order to comply with exhaust emission regulation. As measures against exhaust gas in diesel engines or other machines to date, an exhaust gas recirculation (EGR) device for returning part of exhaust gas to an intake side is provided to reduce a combustion temperature and thereby reduce the amount of nitrogen oxide (NOx) in the exhaust gas. Specifically, the proposed devices include a configuration using an improved exhaust gas purifier for use in a diesel engine (see, for example, Patent Literatures 1: PTL 1) and a configuration in which the number of parts of a blow-by gas returning device is reduced in order to simplify a maintenance and inspection work (see, for example, Patent Literature 2: PTL 2), for example. Another proposed technique is that lubricating oil is separated from a blow-by gas that has leaked from a combustion chamber and the blow-by gas from which lubricating oil has been separated is returned to an intake system for recirculation.